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Oxidative stress (OS) has been thought to play a main role in the etiopathogenesis of recurrent aphthous stomatitis (RAS), which is one of the most common oral mucosal diseases characterized by recurrent and painful oral ulcers. The aim of this investigation was to evaluate the enzymatic antioxidants status in patients with RAS in the active stage and remission stage.Ninety-seven patients with idiopathic minor RAS and 102 race-, age- and gender-matched healthy individuals were recruited. All these subjects were allocated to three groups: RAS patients with active lesion (group A); the same patients in group A in the remission stage of RAS (group B); and healthy individuals without RAS (group C). Following an overnight fast, blood samples were obtained. The serum levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSHPx) were measured by the spectrophotometric method. Independent-samples t-test and paired t-test were performed for statistical evaluation.The serum levels of SOD, GSHPx, and CAT (83.9 ± 17.1 U/ml, 6687.2 ± 2629.2 U/ml, 1789.7 ± 593.8 U/l) were found to be significantly lower in group A as compared to those of group B (99.8 ± 11.1 U/ml, 9364.1 ± 1607.9 U/ml, 2789.1 ± 1113.4 U/l; P0.05) or group C (97.3 ± 12.1 U/ml, 9246.2 ± 2376.1 U/ml, 2819.0 ± 914.8 U/l; P0.05). No significant differences were found between group B and group C with respect to any one of these enzymatic antioxidants (P0.05).Our results indicate that enzymatic antioxidant defense system is impaired in RAS patients with active lesion and seems to play a crucial role in its pathogenesis.

Coupling CE-based separation techniques to MS creates a powerful platform for analysis of a wide range of biomolecules from complex samples because it combines the high separation efficiency of CE and the sensitivity and selectivity of MS detection. ESI and MALDI, as the most common soft ionization techniques employed for CE and MS coupling, offer distinct advantages for biomolecular characterization. This review is focused primarily on technological advances in combining CE and chip-based CE with ESI and MALDI-MS detection in the past five years. Selected applications in the analyses of metabolites, peptides, and proteins with recently developed CE-MS platforms are also highlighted.

Herein we report the first attempt of coupling multidimensional separations to matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging detection. Complex neuropeptide mixtures extracted from crustaceans were first fractionated by reversed-phase liquid chromatography (RPLC), and then subjected to a capillary electrophoresis-mass spectrometric imaging platform. With a specific focus on orcokinin family neuropeptides, we demonstrated that these trace-level analytes from complex neural tissue samples can be fully separated from chemical noise and interfering components and visualized as mass spectrometric imaging signals. A total of 19 putative orcokinins were detected, with highly efficient separations within the family being achieved for the first time. The results indicate that two-dimensional separation coupling to mass spectrometric imaging can serve as a novel and powerful tool in proteomics and peptidomics studies.

Herein, we report an immobilized pH gradient (IPG) capillary isoelectric focusing-matrix-assisted laser desorption/ionization mass spectrometry (CIEF-MALDI MS) platform designed for the separation of complex neuropeptides. This platform features a poly(glycidyl methacrylate-divinylbenzene) (GMA-DVB)-based monolithic column for CIEF separation. Different from regular CIEF, carrier ampholytes are preimmobilized on the monolithic surface instead of being added to the sample. An off-line coupling of IPG-CIEF to MALDI MS has been established. Comparison with regular CIEF and optimizations are performed with bovine serum albumin tryptic peptides and extracted neuropeptide mixtures from crustacean Callinectes sapidus. It has been demonstrated that the separation of complex peptide mixtures in neutral and basic pH ranges can be achieved in less than 10 min with comparable separation efficiency with regular CIEF, while the MS signal is significantly enhanced when employing IPG-CIEF. Enhanced neuropeptide detection is also observed after coupling IPG-CIEF with MALDI MS.